Circuit-breaker.



Patented Nov. I9, lmol.

R. H. READ.

CIRCUIT BREAKER. {Applieacionmed .my 1s, 1901.)

(No Model.)

lnven Robert HRead,

UNITEDy STATES PATENT Price.

ROBERT II. READ, OE SOHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEV YORK.

CHRCUT- SPECIFICATION forming part of Letters Patent No. 687,065, datedNovember 19, 1901. Application filed July'l 8, 1901. Serial No. 68,719.(No model.)

T @ZZ whom t may concern:

Be it known that I, ROBERT II. READ, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements inCircuit-Breakers, (Oase No. 2,192,) of which the following is aspeciiication.

In the operation of modern.circuit-breakers,

Io and particularly those of the magnetic blowout type, in whichbridging and shunt contact-s are employed, a pitting of the main orbridging contact results from the considerable difference of potentialin the two branches due to the impedance of the blow-out magnet when thebridging contact opens the main path of current. -It is the object of myinvention to prevent or reduce this pitting by furnishing theshunt-contact with a path of zo low impedance at the time the main orbridging contact opens.

In carrying out my invention I provide the.

3 5 out during the early part of the opening movement of thecircuit-breaker.

The several features of novelty will be more particularly hereinafterdescribed,and will be definitely indicated in the claims appended' tothis specification.

In the accompanying drawing, which illustrates the invention as appliedto a recent commercial form of circuit-breaker, 1 represents asupporting-panel, of reproof insulating material-such, for example, asslate or marble-on which aremounted terminals 2 2, connected when thecircuit is closed by a bridging contact 3, formed of a bundle ofcompactly-arranged laminae of copper, phos- 5o phor-bronze, or othergood conducting metal.

I This is pivotally supported on a link 4f., pivoted near the lowerterminal,and is connected by a toggle 5 with a frame G, pivoted at apoint between the terminals. To one member of the cramping-toggle isfixed a handle 7, by which the toggle may be cramped and thecircuit-breaker closed with a hard pressure on its bridging contact. Thetype of breaker shown is provided with a trip device comprising a bundleof iron laminae 8, includ- 6o ing three sides of the lower terminal andadapted to be magnetized thereby and coperating with an armature 9,connected with a trip-rod 10, for collapsing the toggle. These featuresform no essential part of my improvements and are described merely byway of illustration. The shunt-contact 11 may be connected with oneterminal in any suitable manner by a permanent connection, and

the breaking end rests when the circuit- 7o breaker is closed on a metalface integral with or in good conductive relation to the terminal 2. Theface is preferably part of a metallic extension of the terminal 2, asindicated in the drawingn The shunt-contact is provided with an arcingtip, composed jointly of metal and carbon, as indicated at l2, in whichau opening movement of the circuit-breaker effects a sliding movementover the face of the terminal. The extent of this movement may 8o begraduated according to the potential of the current to be broken, thedesign in all cases being such as to permit the main contact to leave asafe air-gap between its contact-faces and the terminals before theshuntcontact opens engagement with the terminal.

In the same plane with the extension for the shunt-contact is a metalliccontact-piece 13, connected with one terminal of a blow-out coil 14, theother terminal of the blow-out 9o -coil being connected with theterminal 2. The contact 13 is insulated from the terminal. The distancebetween the adjoining faces of the contact 13 and the terminal eX-tension is such that the shunt-'contact will 95 bridge the gap withoutopening the circuit. The shunt-contact is preferably compound incharacter, the trailing end being ot' carbon and the leading end ofmetal, as indicated in the drawing. The ends of the core of the rooblow-out coil are provided with extension pole-pieces, one of which isseen at 15, to

provide a magnetic field inclosing the rupturing-point of theshunt-contact. The terminal face of the contact 13 may also be ofcarbon. With this organization in opening` the circuit the main contactis first opened, While a non-inductive shunt of very small impedancepermits current to readily pass and creates a very slight drop ofpotential across the gaps between the terminals and the bridgingContact, thus effectively eliminating arcing at this point. After a saferange of movement the blow-out coil is connected in circuit by theshunt-contact and the arc finally extinguished when .the contact betweenthe extension-terminal 13 and the shunt arcing tip is broken, this arcbeing instantly extinguished by a magnetic field between the polepiecesproduced by the blowout coil 14:.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. A circuit-breaker provided with main and shunt contacts, a path ofloW impedance for the shunt-contact when the main contacts areseparated, and a blow-outcoil cut into circuit before nal rupture.

2. A circuit-breaker provided with main and shunt contacts, both havingnon-inductive paths when the circuit is closed, and an auxiliary branchincluding` a blow-out coil cut into the shunt-circuit after the maincontact has moved through a definite air-gap 3. A circuit-breakerprovided with main and shunt contacts, both having non-induct iveconnections with the terminals, means for prolonging the non-inductiveconnection of the shunt until the main contacts have opened a definitedistance, and a blow-out coil cut into circuit before the shunt isopened.

4:. A circuit-breaker provided with main and shunt contacts, both innon-inductive relation to the circuit, means for maintaining thenon-inductive shunt connection until the main contact has opened adeterminate distance, a normally open branch including a blow-out coil,and means for closing this branch before the circuit is broken.

In Witness whereof I have hereunto set my hand this 15th day of July,1901.

ROBERT ll. READ.

Vitnesses:

BENJAMIN B. HULL, FRED RUss.

